The object of the present invention consists in searching for possible solutions to the problem when designing the bearing points for generic boom structures.
This object is solved by a boom for an earth-moving machine, in particular an excavator, comprising one or more bearing plates for supporting a cylinder unit, wherein at least one bearing plate includes an end-side curvature extending outwardly to a lateral edge of the boom, a boom upper side is broadened in a region of the outwardly running bearing plate or plates, and the bearing plate or plates extend up to the broadened boom upper side. Advantageous aspects of the boom are subject-matter of the dependent claims. In connection with the invention, the term boom is used comprehensively. For example, it also comprises a so-called dipper arm.
According to the invention, it is proposed for the generic boom to configure the bearing plate or plates with a curvature which at the end extends outwardly to the lateral edge of the boom. The invention applies both to boom configurations with only one bearing plate and to configurations with two or more bearing plates. For the sake of simplicity, the invention and its advantageous embodiments will always be described below with reference to a configuration with two bearing plates, but the following explanations equally apply to a boom configuration with only one or more than two bearing plates.
In a configuration with a plurality of bearing plates the same accordingly no longer extend parallel in the end portion, but the distance between the bearing plates increases. The special curvature in the end region of the bearing plates, in particular in the end region of the bearing plates facing the boom tip, has an advantageous effect on the resulting mechanical stiffness of the boom, in particular in the region of the arranged bearing plates, as the dissipation of force from the bearing point into the boom can be distributed better. Ideally, possible reinforcing plates, as they are commonly used in the prior art, thereby can be omitted. Moreover, the plate thickness of the bearing plates can be reduced. In total, the construction according to the invention permits a distinct weight reduction. The lower expenditure of material and time in the manufacture of the boom according to the invention provides for a positive saving of costs.
According to the invention, at least one bearing plate or both bearing plates at their ends is/are guided up to the edge of the boom upper side and adjoins/adjoin the formed edge of the boom surface with the side faces. Furthermore, it is provided here that the boom upper side is broadened in the region of the outwardly running bearing plates, i.e. the entire boom profile is designed broader in the region of the at least one bearing plate or the adjacent bearing plates so that the latter are extended beyond the original edge between surface and side part and are positioned on the expanded boom region, i.e. the lateral broadening of the boom. Due to this construction, the ends of the bearing plates are loaded less.
According to a preferred embodiment, the bearing plate or plates can be perpendicularly attached to the boom upper side.
The boom can cohesively be assembled from a rear and a front boom part to obtain a boomerang-like boom structure, but the invention in principle can be used for any boom structure.
It is conceivable that the bearing plates extend outwardly each with an identical radius of curvature. It is likewise conceivable, however, to provide individual bearing plates with different radii of curvature.
The proposed bearing plate or plates serve for supporting a cylinder that serves for actuating an attachment mounted on the boom and/or a boom extension. The corresponding attachment additionally can include a corresponding boom extension, wherein a corresponding cylinder unit then serves for actuating the boom extension.
Furthermore, it is preferred when the curvature of the bearing plate or plates directly adjoins a bolt receptacle of the bearing plates. Corresponding bearing plates usually are formed by a bearing plate which in the region of the broadest point provides an appropriate bore for receiving a bearing bolt. In the direction of the boom foot the width of the bearing plates usually can be reduced steadily. In the direction of the boom tip an abrupt reduction of the plate width preferably is effected, wherein the bearing plate reduced in width then is guided outwardly to the edge of the boom surface with a corresponding radius of curvature.
The boom construction is assembled from at least one front and at least one rear boom part. The bearing plate or plates for example at least for the most part can extend on the boom upper side of the front boom part. According to a preferred aspect of the invention at least one upper connecting plate can be provided in the connecting region between the boom parts, which ideally represents a part of the boom upper side in the connecting region of the boom parts. The connecting plate provides an appropriate curvature depending on the angle of the two boom parts relative to each other. In the case of such a special construction of the boom it is particularly advantageous when the bearing plates extend from the boom upper side of the front boom part to the upper connecting plate. At their ends, the bearing plates usually welded to the boom parts then reach into a boom region loaded less onto the connecting plate. The welding seams necessary there accordingly are subject to a lower stress load, which has a positive effect on their fatigue resistance. An otherwise necessary aftertreatment of the welding seams might be omitted.
Beside the inventive boom the present invention also relates to an earth-moving machine, in particular an excavator with at least one boom according to the present invention. The advantages and properties of the earth-moving machine accordingly quite obviously correspond to the advantages and properties discussed already in connection with the excavator boom according to the invention, which is why a repetitive description is omitted at this point.
Further advantages and properties of the invention will be explained in detail below with reference to an exemplary embodiment illustrated in the Figures.